sssd/0010-util-sss_ptr_hash-fixed-double-free-in-sss_ptr_hash_.patch

53 lines
1.7 KiB
Diff

From 26e33b1984cce3549df170f58f8221201ad54cfd Mon Sep 17 00:00:00 2001
From: Alexey Tikhonov <atikhono@redhat.com>
Date: Tue, 7 Jan 2020 16:29:05 +0100
Subject: [PATCH] util/sss_ptr_hash: fixed double free in
sss_ptr_hash_delete_cb()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Calling data->callback(value->ptr) in sss_ptr_hash_delete_cb() could lead
to freeing of value->ptr and thus to destruction of value->spy that is
attached to value->ptr.
In turn sss_ptr_hash_spy_destructor() calls sss_ptr_hash_delete() ->
hash_delete() -> sss_ptr_hash_delete_cb() again and in this recursive
execution hash entry was actually deleted and value was freed.
When stack was unwound back to "first" sss_ptr_hash_delete_cb() it tried
to free value again => double free.
To prevent this bug value and hence spy are now freed before execution of
data->callback(value->ptr).
Resolves: https://pagure.io/SSSD/sssd/issue/4135
Reviewed-by: Pavel Březina <pbrezina@redhat.com>
---
src/util/sss_ptr_hash.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/util/sss_ptr_hash.c b/src/util/sss_ptr_hash.c
index c7403ffa6..8f9762cb9 100644
--- a/src/util/sss_ptr_hash.c
+++ b/src/util/sss_ptr_hash.c
@@ -154,13 +154,13 @@ sss_ptr_hash_delete_cb(hash_entry_t *item,
callback_entry.value.type = HASH_VALUE_PTR;
callback_entry.value.ptr = value->ptr;
+ /* Free value, this also will disable spy */
+ talloc_free(value);
+
/* Switch to the input value and call custom callback. */
if (data->callback != NULL) {
data->callback(&callback_entry, deltype, data->pvt);
}
-
- /* Free value. */
- talloc_free(value);
}
hash_table_t *sss_ptr_hash_create(TALLOC_CTX *mem_ctx,
--
2.20.1